traces on fired bullets

Method of the Binarization of Images of Traces on the Shot Bullets for the Automatic Assessment of Their Suitability to Identification of the Fierarms

Introduction. Nowadays, automatic identification of weapons on electronic databases involves the analysis thousands of images of similar tracks, including images which are not suitable for identification. It is necessary to exclude from the analysis traces not suitable for identification for reduction of volume of calculations and increase of their efficiency. The aim of this work is the analysis of methods for assessing the suitability of traces to the identification and develop image binarization techniquie, which ensures minimal distortion of the width tracks on traces on the shot bullets. Theoretical analysis. There are two methods for evaluating of the suitability of dynamic traces to identify the weapon. The first is to count the number of lines, the width of the tracks and the spaces between them. The second is to find the autocorrelation function (ACF). The ACF form is close to a delta function form for a trace suitable for identification. The second method is more promising for the analysis of traces on the shot bullets. Experimental part. The authors proposed an image binarizatiom technique based on the construction of the image brightness profile. Application of this technique to images of dynamic traces, which are oriented vertically, allows adequately display the main tracks on binary images. Conclusion. The proposed method allows to get a binary image of traces on the shot bullets suitable for automatic analysis of their suitability for identifying and further comparing traces.

Problems of Ensuring Compliance of Technical Characteristics of Civil and Office Firearms to Criminalistic Requirements of the Ministry of Internal Affairs of Russia

Introduction. Problematic issues of providing the criminalistic requirements of the Ministry of Internal Affairs of Russia imposed to firearms are considered in work. A sometimes weapons does not provide formation on the shot bullets and cartridge cases of the traces suitable for identification. Absence of any standards or specifications on a roughness of a relief of surfaces of the details forming traces is to it the reason. In addition, arms manufacturers poorly represent modern methods and technical means of identification of the weapon. Experimental part. In work the reasons of formation of traces on the shot bullets and shot cartridge cases not suitable for identification of the weapon are analyzed. Cases where the identification of the weapons on the striker traces is impossible due to the design of shells hunting cartridges are shown in the article. The negative influence of the production of primers traces at identifying of weapons on firing pin traces is quickly studied. Conclusion. Forensic requirements for identification of the weapon can be most effectively provided at close scientific and technical cooperation of the arms manufacturers and scientists specializing in area of judicial identification of the weapon.